This paper investigates how intra-industry trade (IIT) is linked to cross-country income difference and foreign direct investment (FDI). We distinguish IIT as either horizontally or vertically differentiated, using bilateral exports and imports data for Japan and the remaining East Asian countries at the SITC five-digit level over 1990–2000. Our results show that the income difference has a negative relationship with the share of horizontal IIT, but a positive relationship with vertical IIT, and that cross-country FDI has a positive relationship with share of horizontal IIT and a negative relationship with share of vertical IIT.